| Message ID | 20180627171720.27028-7-leif.lindholm@linaro.org |
|---|---|
| State | New |
| Headers | show |
| Series | efi: arm linux loader unification and correctness | expand |
On Wed, Jun 27, 2018 at 06:17:20PM +0100, Leif Lindholm wrote: > The 32-bit arm Linux kernel is built as a zImage, which self-decompresses > down to near start of RAM. In order for an initrd/initramfs to be > accessible, it needs to be placed within the first ~768MB of RAM. > The initrd loader built into the kernel EFI stub restricts this down to > 512MB for simplicity - so enable the same restriction in grub. > > For arm64, the requirement is within a 1GB aligned 32GB window also > covering the (runtime) kernel image. Since the EFI stub loader itself > will attempt to relocate to near start of RAM, force initrd to be loaded > completely within the first 32GB of RAM. > > Signed-off-by: Leif Lindholm <leif.lindholm@linaro.org> > --- > grub-core/loader/arm64/linux.c | 39 ++++++++++++++++++++++++++++++++++++++- > 1 file changed, 38 insertions(+), 1 deletion(-) > > diff --git a/grub-core/loader/arm64/linux.c b/grub-core/loader/arm64/linux.c > index 577fbda54..0d550182f 100644 > --- a/grub-core/loader/arm64/linux.c > +++ b/grub-core/loader/arm64/linux.c > @@ -193,6 +193,42 @@ grub_linux_unload (void) > return GRUB_ERR_NONE; > } > > +/* > + * This function returns a pointer to a legally allocated initrd buffer, > + * or NULL if unsuccessful > + */ > +static void * > +allocate_initrd_mem (int initrd_pages) > +{ > + grub_addr_t max_addr; > + > + if (grub_efi_get_ram_base (&max_addr) != GRUB_ERR_NONE) > + return NULL; > + > + /* > + * As per linux/Documentation/arm/Booting > + * ARM initrd needs to be covered by kernel linear mapping, > + * so place it in the first 512MB of DRAM. > + * > + * As per linux/Documentation/arm64/booting.txt > + * ARM64 initrd needs to be contained entirely within a 1GB aligned window > + * of up to 32GB of size that covers the kernel image as well. > + * Since the EFI stub loader will attempt to load the kernel near start of > + * RAM, place the buffer in the first 32GB of RAM. > + */ > +#ifdef __arm__ > +#define INITRD_MAX_ADDRESS_OFFSET (512U * 1024 * 1024) > +#else /* __aarch64__ */ > +#define INITRD_MAX_ADDRESS_OFFSET (32ULL * 1024 * 1024 * 1024) > +#endif May I ask you to move these definitions together with the comment before the allocate_initrd_mem(). Or even to the beginning of the file just behind GRUB_MOD_LICENSE(). I prefer the latter. Though I am not insisting on it. Daniel _______________________________________________ Grub-devel mailing list Grub-devel@gnu.org https://lists.gnu.org/mailman/listinfo/grub-devel
On Fri, Jul 06, 2018 at 06:00:11PM +0200, Daniel Kiper wrote: > On Wed, Jun 27, 2018 at 06:17:20PM +0100, Leif Lindholm wrote: > > The 32-bit arm Linux kernel is built as a zImage, which self-decompresses > > down to near start of RAM. In order for an initrd/initramfs to be > > accessible, it needs to be placed within the first ~768MB of RAM. > > The initrd loader built into the kernel EFI stub restricts this down to > > 512MB for simplicity - so enable the same restriction in grub. > > > > For arm64, the requirement is within a 1GB aligned 32GB window also > > covering the (runtime) kernel image. Since the EFI stub loader itself > > will attempt to relocate to near start of RAM, force initrd to be loaded > > completely within the first 32GB of RAM. > > > > Signed-off-by: Leif Lindholm <leif.lindholm@linaro.org> > > --- > > grub-core/loader/arm64/linux.c | 39 ++++++++++++++++++++++++++++++++++++++- > > 1 file changed, 38 insertions(+), 1 deletion(-) > > > > diff --git a/grub-core/loader/arm64/linux.c b/grub-core/loader/arm64/linux.c > > index 577fbda54..0d550182f 100644 > > --- a/grub-core/loader/arm64/linux.c > > +++ b/grub-core/loader/arm64/linux.c > > @@ -193,6 +193,42 @@ grub_linux_unload (void) > > return GRUB_ERR_NONE; > > } > > > > +/* > > + * This function returns a pointer to a legally allocated initrd buffer, > > + * or NULL if unsuccessful > > + */ > > +static void * > > +allocate_initrd_mem (int initrd_pages) > > +{ > > + grub_addr_t max_addr; > > + > > + if (grub_efi_get_ram_base (&max_addr) != GRUB_ERR_NONE) > > + return NULL; > > + > > + /* > > + * As per linux/Documentation/arm/Booting > > + * ARM initrd needs to be covered by kernel linear mapping, > > + * so place it in the first 512MB of DRAM. > > + * > > + * As per linux/Documentation/arm64/booting.txt > > + * ARM64 initrd needs to be contained entirely within a 1GB aligned window > > + * of up to 32GB of size that covers the kernel image as well. > > + * Since the EFI stub loader will attempt to load the kernel near start of > > + * RAM, place the buffer in the first 32GB of RAM. > > + */ > > +#ifdef __arm__ > > +#define INITRD_MAX_ADDRESS_OFFSET (512U * 1024 * 1024) > > +#else /* __aarch64__ */ > > +#define INITRD_MAX_ADDRESS_OFFSET (32ULL * 1024 * 1024 * 1024) > > +#endif > > May I ask you to move these definitions together with the comment before > the allocate_initrd_mem(). Or even to the beginning of the file just > behind GRUB_MOD_LICENSE(). I prefer the latter. Though I am not > insisting on it. I'm OK with either. I stuck it here because it is information that is _only_ relevant to this particular piece of code. So my preference leans the other way. Will update for v4. / Leif _______________________________________________ Grub-devel mailing list Grub-devel@gnu.org https://lists.gnu.org/mailman/listinfo/grub-devel
diff --git a/grub-core/loader/arm64/linux.c b/grub-core/loader/arm64/linux.c index 577fbda54..0d550182f 100644 --- a/grub-core/loader/arm64/linux.c +++ b/grub-core/loader/arm64/linux.c @@ -193,6 +193,42 @@ grub_linux_unload (void) return GRUB_ERR_NONE; } +/* + * This function returns a pointer to a legally allocated initrd buffer, + * or NULL if unsuccessful + */ +static void * +allocate_initrd_mem (int initrd_pages) +{ + grub_addr_t max_addr; + + if (grub_efi_get_ram_base (&max_addr) != GRUB_ERR_NONE) + return NULL; + + /* + * As per linux/Documentation/arm/Booting + * ARM initrd needs to be covered by kernel linear mapping, + * so place it in the first 512MB of DRAM. + * + * As per linux/Documentation/arm64/booting.txt + * ARM64 initrd needs to be contained entirely within a 1GB aligned window + * of up to 32GB of size that covers the kernel image as well. + * Since the EFI stub loader will attempt to load the kernel near start of + * RAM, place the buffer in the first 32GB of RAM. + */ +#ifdef __arm__ +#define INITRD_MAX_ADDRESS_OFFSET (512U * 1024 * 1024) +#else /* __aarch64__ */ +#define INITRD_MAX_ADDRESS_OFFSET (32ULL * 1024 * 1024 * 1024) +#endif + + max_addr += INITRD_MAX_ADDRESS_OFFSET - 1; + + return grub_efi_allocate_pages_real (max_addr, initrd_pages, + GRUB_EFI_ALLOCATE_MAX_ADDRESS, + GRUB_EFI_LOADER_DATA); +} + static grub_err_t grub_cmd_initrd (grub_command_t cmd __attribute__ ((unused)), int argc, char *argv[]) @@ -221,7 +257,8 @@ grub_cmd_initrd (grub_command_t cmd __attribute__ ((unused)), grub_dprintf ("linux", "Loading initrd\n"); initrd_pages = (GRUB_EFI_BYTES_TO_PAGES (initrd_size)); - initrd_mem = grub_efi_allocate_any_pages (initrd_pages); + initrd_mem = allocate_initrd_mem (initrd_pages); + if (!initrd_mem) { grub_error (GRUB_ERR_OUT_OF_MEMORY, N_("out of memory"));
The 32-bit arm Linux kernel is built as a zImage, which self-decompresses down to near start of RAM. In order for an initrd/initramfs to be accessible, it needs to be placed within the first ~768MB of RAM. The initrd loader built into the kernel EFI stub restricts this down to 512MB for simplicity - so enable the same restriction in grub. For arm64, the requirement is within a 1GB aligned 32GB window also covering the (runtime) kernel image. Since the EFI stub loader itself will attempt to relocate to near start of RAM, force initrd to be loaded completely within the first 32GB of RAM. Signed-off-by: Leif Lindholm <leif.lindholm@linaro.org> --- grub-core/loader/arm64/linux.c | 39 ++++++++++++++++++++++++++++++++++++++- 1 file changed, 38 insertions(+), 1 deletion(-) -- 2.11.0 _______________________________________________ Grub-devel mailing list Grub-devel@gnu.org https://lists.gnu.org/mailman/listinfo/grub-devel